Risk of chlamydial PID and oral contraceptives.
D016022:Case-Control Studies; D002690:Chlamydia Infections / Q000209:etiology*; D003276:Contraceptives, Oral; D005260:Female; D006801:Humans; D015999:Multivariate Analysis; D000292:Pelvic Inflammatory Disease / Q000209:etiology*; D011247:Pregnancy; D011271:Pregnancy, Ectopic; D012307:Risk Factors
D003276:Contraceptives, Oral